Simulations and experimental research of fiber optic contrast-based dislocation sensor

Abstract

The dislocation sensor based on the contrast phenomenon in an unbalanced fiber optic Michelson interferometer with a 3 x 3 coupler and a semiconductor multimode laser. Periodic contrast oscillations, which depend on a laser spectrum, occur if a measuring arm of the interferometer is elongated. A conception of the elongation sensor that based on linearization of contrast oscillations is shown. A virtual model of the sensor was built for simulations. For real parameters of 1 -m long sensor, 5-mm measuring range with 12-µm uncertainty was obtained. Next, a setup of the sensor and signal processing scheme of real sensor is presented. During measurements we obtained 5-mm measuring range with ± 28-µm uncertainty. Explanation of these differences and conclusion to further research are formulated.